/*
 * Copyright 2014 Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <stdint.h>
#include <sys/types.h>

#include <folly/portability/SysTime.h>

namespace apache { namespace thrift { namespace util {

class PausableTimer {
  public:
    explicit PausableTimer(int timeLimit=0);

    void reset();
    void start();
    void stop();

    // isTimeLimitFinite_ && totalTimed_ > timeLimit_
    bool hasExceededTimeLimit();

    // limit_in_microseconds == 0 implies there is no time limit to
    // exceed, i.e. that this method will return false.
    bool didLastRunningTimeExceedLimit(uint64_t limit_in_microseconds);

  private:
    bool isTimeLimitFinite_;
    bool paused_;
    struct timeval timeLimit_;

    // time at which timer went from paused to running (not paused)
    // state
    struct timeval startTime_;

    // time timer has run, i.e. not been paused, since last reset
    struct timeval totalTimed_;

    // time elapsed between latest pause and the start before it
    struct timeval lastRunningTime_;
};

}}}
